Paul Vo, Acoustic Synthesis, and Revolutionary Handpan Sounds

Paul Vo, Acoustic Synthesis, and Revolutionary Handpan Sounds

It is still hard for us to believe the sound in the following video is actually coming from the handpan even when we are in the same room as it much less in a video. We have done what we can to show that the sound is in fact coming from the handpan by dropping sand on the vibrating membrane as well as muffling the sound at times. The voice you hear was prerecorded and then driven into the vibration of the note membrane utilizing a magnetic field generated by the device. The device itself makes no sound. It only creates a silent programmable magnetic field.

All sound is coming from the actual handpan membranes in the video!

Back Ground on this Project

Mark and Josh have been thoroughly intrigued and excited to collaborate over the past few months with Paul Vo of Vo Inventions. Paul is a brilliant inventor and product developer who’s work has resulted in the Moog Guitar, the VO-96 and the VO Wond, which all utilize Paul’s patented vibration control technology to influence and activate the vibrations of ferrous guitar strings. The popular Ebow is another example of a device based on different technology invented by Greg Heet and patented back in 1979. Paul’s new technology is uniquely capable of controlling individual harmonics of vibration in a predictable way.

Mark and Paul met each other in 2014 at a local musical instrument builders concert in Asheville, North Carolina. They were very curious by each other’s work and discussed the potential of collaboration some day. That day finally arrived in later 2016. After initial discussions between Mark, Paul and Josh about the physics of the Saraz as well as Paul’s other magnetic oscillators, Paul designed and built a prototype magnetic oscillator that is capable of driving the vibration of a handpan. Currently referred to as the “Saraz Sonic Driver” or “Harmonic Spider”, the device is similar to his other inventions, which are capable of using a programmable magnetic field to activate and drive vibration in ways that are not possible with any other physical force.

We are not the first to use a magnetic oscillator on a handpan. Years after Thomas Rossing’s Holographic Inferometry research on the Hang ®, we saw Marty of Sunpan use an Ebow like device to activate the fundamental and harmonics on one of his instruments. Similar technology has also been used on an Innersound. What makes our prototype magnetic driver special however is that we are not limited only by activation of the most prominent frequencies within a note such as the fundamental and harmonics. This device is programmable and can actually drive an enormous range of frequencies and complex timbres into the membrane of a handpan. Paul refers to this technology as “Acoustic Synthesis”, which is taking a digital signal to program a magnetic field that can drive ferrous material vibration.

Basically, the magnetic driver can turn the handpan into a speaker.

While the speaker is limited by the physically possible vibrations of a handpan note membrane, we have discovered to our great surprise that the membrane is in fact capable of far more vibration and complexity than we ever imagined possible even as builders of these instruments.

After Paul finished the prototype, he came over to Josh Rivera’s studio for the initial demonstration of what it can do. Within the first hour of Paul’s demonstration, we heard things come from the handpan that we had never imagined including isolated harmonics that are never prominent enough to be heard beyond the underlying timbre of a note. What was even more surprising and exciting was being able to speak into a microphone and hear our voices come out of the handpan membrane. We quickly realized that we could drive the device with an enormous array of inputs including other musical instruments, Pro Tools plugins, Ableton Live or even a sound file such as an MP3. This is where Josh’s background in recording engineering become incredibly valuable once again.

Josh has since clocked many hours exploring what is possible with Pro Tools and more recently with the seemingly limitless options of Ableton Live. However, he has barely begun to explore what is possible with this novel interaction of a programmable magnetic field driving vibration and therefore sound through a Handpan membrane. One thing that we find fascinating is how strongly the vibration is driven through the membrane. While we can somewhat muffle the sound, we have never succeeded in completely muffling particularly the higher frequencies even if we cover the entire handpan with a pillow or blanket.

We have also barely begun exploring how to utilize this device on any Handpan much less design a Saraz that is specifically tailored to the device. It appears that brighter drums are easier to drive for certain signals but can also have greater distortion while other signals sound better on more controlled drums.

In the video above, two Saraz were used. Mark’s voice, the Star Wars Theme and John Lennon’s Imagine were recorded on a 21″ diameter C# Minor Saraz that had a relatively controlled center note membrane. We found that we got the clearest signal from this drum particularly for the prerecorded segments of Mark’s voice. You may have noticed that the driver has two legs on the dimple. We did this in order to further control the particularly active vibration of the long axis.

In the MIDI clip with Josh and Mark, we used a 20″ Diameter F# minor Saraz. For this signal, we found that the driver worked best with all of the legs in the interstitial area around the center note while the driver was placed over one side of the long axis about where Josh drops the sand. This drum was a bit more bright and seemed to pick up the MIDI signal with more clarity and prominence relative to the more controlled notes that we had available. In this clip, F#4 activates the membrane the most, which Mark plays numerous times on the keyboard. This is the note that gets the sand most excited as the center note is an F#3 with an F#4 octave harmonic on the long axis. When we played the F#4 on the MIDI keyboard, it also strongly activated the side note F#4 as well as the highest C#5 note even though the driver was not near either of those notes. At 3:48-3:49, Josh briefly mutes the side F#4 which is on the far side of the drum from the camera. This cross activation of multiple notes is likely due to the coupling of the specific drum. A similar dynamic happens in the beginning of the video when Mark is speaking. The note that he briefly sings to show the activation of the sand is C#4 while the center note is a C#3 with a C#4 octave harmonic on the long axis of the membrane.

In all of the video, the Magnetic Driver is not actually touching the membrane, hence why it has six legs to elevate it above the membrane. If it touches, it will vibrate against the membrane and rattle. The closer it gets to the membrane however, the stronger the drive and signal due to the magnetic field being closer to the ferrous membrane.

We have also used the device on numerous side notes which of course also activate. We have also attached the driver to the bottom shell of the drum and been able to activate all of the notes on the top shell, however it requires much more amplitude than this first prototype device is designed to generate.

We have months of further research to do before even considering if this is a viable commercial product to offer within an already small niche art form. However, this technology has already inspired a lot of creativity and novel ideas that go far beyond sound production. Even at this early stage of research and design, we have been so astounded by such revolutionary sounds coming from a handpan that we have felt overwhelmingly compelled to share it with the world. In time, we will be publish more videos of Saraz being played along with the almost endless signals that can be utilized to drive this magnetic oscillator.